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Odd shifting and power loss question

Discussion in 'Towing & Hauling' started by Rhubarb Johnson, Oct 23, 2017.

  1. Oct 23, 2017 at 12:15 PM
    #1
    Rhubarb Johnson

    Rhubarb Johnson [OP] New Member

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    New windshield wipers....just getting started
    Towing the 5k camper through Kentucky/Tennessee hills had something unusual happen twice and not sure if it is common.

    Sailing through moderate hills at about 60mph with the cruise control, Engine turning at about 2200 rpm and suddenly revved up 3500 and felt sudden deceleration. Almost like the transmission was slipping all the sudden. About 5 seconds and a "what the heck" later she shifted again and 2200.

    What's weird, she upshifted multiple times on the trip but never felt this odd shift slow down. Just felt odd. Knew this group would know.

    I was never able to duplicate this without cruise and only occurred a few times on cruise. And I can't remember if I was in tow/haul mode.

    Only have 15k on the truck and want to make sure there isn't a problem before the warrantee runs out....
     
  2. Oct 23, 2017 at 12:24 PM
    #2
    ToyotaTundraMike

    ToyotaTundraMike Not A New Member

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    I have had a similar instance occur going downhill on some moderate hills without towing anything. It always catches me off guard and I forget to make a mental note of the RPM. For me its when I’m going kind of fast and start going downhill I take off the gas and try to coast and its like it tricks the transmission into downshifting and then after it does it makes a loud sound (assume this is when yours hits 3500 or so) like it wasnt meant to downshift. I can’t recall if cruise control has been on at the time or not.
     
  3. Oct 23, 2017 at 12:59 PM
    #3
    Rhubarb Johnson

    Rhubarb Johnson [OP] New Member

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    New windshield wipers....just getting started
    Very strange. I was actually climbing a slight grade at the time.

    One thing I like, is she'll hold a gear for engine braking when going down slight grades if you tap the brakes.
     
    kenomouth64 likes this.
  4. Oct 23, 2017 at 1:50 PM
    #4
    kenomouth64

    kenomouth64 New Member

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    Hold the Line! If you are not holding the line, abandon your ship. Destruction is inevitable without more to hold the line!
    I cannot say I have experienced that. My guess is that it has something to do with an "electronic slip-up". The traction control system might have thought it detected slipping and applied the brakes to correct for slippage. I am not a fan of the electronic traction control systems...

    My guess is it was just a slip-up with the traction control system thinking it was loosing traction or it might have lost traction.
     
  5. Oct 23, 2017 at 7:58 PM
    #5
    Rhubarb Johnson

    Rhubarb Johnson [OP] New Member

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    New windshield wipers....just getting started
    Hmmm...that .makes sense. It was almost like shifting into neutral for a few seconds.
     
  6. Oct 23, 2017 at 8:07 PM
    #6
    Black Wolf

    Black Wolf Bigfoot Hunter, Sasquatch too, but not Yeti

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    Do you have "Tow Haul" option? If you do..push in Tow Haul button.
     
  7. Oct 24, 2017 at 5:57 AM
    #7
    Rhubarb Johnson

    Rhubarb Johnson [OP] New Member

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    New windshield wipers....just getting started
    Many thanks, yup I have the button. Really notice the changed shift points from 0-50 and has power. I can't remember if I was in tow/haul when she upshifted, but will keep watching it. How long is the typical powertrain warrantee on the Tundra?
     
  8. Oct 24, 2017 at 6:07 AM
    #8
    kenomouth64

    kenomouth64 New Member

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    Hold the Line! If you are not holding the line, abandon your ship. Destruction is inevitable without more to hold the line!
    5 Years 60,000 Miles

    I know when I first started using the Tundra a few of the 'oddities' really threw me off. I was not used to things like: grade-braking, traction control, Auto-lsd, etc. I have since got used to them and actually like a few of them (Grade-braking works really well).

    Thinking back I did have something like this happen to me. I was driving on the highway at around 70MPH using cruise control (on a rainy day). When I came up to an incline, the transmission downshifted to 5th gear, then the traction control thought it felt tire slippage (it could have), so it applied the brakes. The motor was revving around 2900 RPM and I was slowing down.

    It has never happened before.
     
  9. Oct 24, 2017 at 11:39 AM
    #9
    Rhubarb Johnson

    Rhubarb Johnson [OP] New Member

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    New windshield wipers....just getting started
    That why I appreciate this site so much. Before the Tundra I had a 2005 SUV, so 12 year of technology improvements to get used to with the Tundra. (People complain about no bells-whistles in Tundra...compared to an '05 there are plenty)

    Grade-braking was something I'd never heard of and I spent months researching before the purchase. "Discovered" it this Summer and thought it was a fluke. Then it kept doing it....

    I'm not worried on the shifting and bet you guys are right. Something detected something a slip or change and it erred on the side of caution.

    Wonder what amazing things they will have in 2027 when it's time to trade...
     
  10. Oct 24, 2017 at 12:01 PM
    #10
    BOBONTUESDAY

    BOBONTUESDAY Grocery Getter

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    It's normal when on cruise for that to happen while going up a steep grade and a good wind doesn't help either. I've had it happen to me a few times while towing. Actually it happened yesterday on a 500 mile trip. That's why I try and throw it in 5th or 6th when I'm on the highway or avoid cruise on a really steep grade.
     
  11. Oct 24, 2017 at 12:21 PM
    #11
    kenomouth64

    kenomouth64 New Member

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    Hold the Line! If you are not holding the line, abandon your ship. Destruction is inevitable without more to hold the line!

    If that legislation I was reading about passes it will likely be an electric truck, if not, then diesel most likely. I am sure it will have all kinds of driver assist features: Adaptive Cruise control, Parallel park assist, trailer back assist, Improved traction control devices, something that will not let you speed ever (I hope not)... There has been talk of chipping speed limit signs and all of the north American vehicles would have to make their vehicle so that it abides by the rules on the chips (speed limits mainly).

    I can see how that technology would be abused so easily and it likely will be a while before something such as that happens. I hope it will be at least!
     

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